SPATEMs transmit the current state of a traffic light (ETSI TS 103 301): which signal groups are red, amber, or green right now — and how the state is expected to change.

A SPATEM contains, among other things:

1. the current phase per signal group (red / amber / green)
2. predicted change times (e.g. “likely green in 12 s”)
3. references to the intersection topology from MAPEM

SPATEMs are sent by C-ITS traffic lights (RSUs), typically several times per second. Together with MAPEM they enable time-to-green displays and speed advisories (GLOSA) — this is what some vehicles show as traffic light information.